Just purchased a 63 Vette that was sitting for about 5years,the person has given me paperwork that the motor was rebuilt about 8-9year ago. The cam that was put in the motor I believe is a TRW # TP-147 so the paper says. Does anyone know anything about this cam? (lift, duration etc) please help.
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Re: Cam Help !!
That's the 3927140 first design (Trans Am) racing cam - very high duration and overlap - designed specifically for headers and open exhaust - requires special high force valve springs - 4500-8000 power band - totally unsuitable for the street.
What was the original engine option, and what it your objective for the car?
Duke -
Re: Cam Help !!
Duke, it's in a fuel injected car, and I would like to drive it about once/ twice a month. Good/Bad?????Comment
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Re: Cam Help !!
The OE FI cam was the "Duntov", but I recommend the LT-1 cam to replace all Duntov cams on SBs with 461 or later big port heads. The Federal Mogul part number for the LT-1 cam is CS1145R. Also change back to the standard '66-up SB valve springs (They're slightly different than the earlier SB valve springs) assuming that the companion high rate springs were installed along with the 140 cam.
The LT-1 cam will provide virtually identical idle quality to the Duntov with about the same bottom end torque with better top end power.
Have you started the engine and driven the car. With the 140 cam it will probably barely idle at 1200-1500, if it will idle at all, and it will have very poor torque below 4500 - in general a rather unpleasant street driving experience.
A high revving cam with an OE '63 long block is a very bad combination considering that the rods are weak, and you should limit revs to 6500 maximum, but not too often.
DukeComment
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Re: However....
If you want to keep your 63 FI car original, and I sure would, it would be best to install a duplicate of the correct original 097 cam that belongs in the car. This cam is available from several aftermarket sources, such as Crane Cams. There's actually quite a difference in the sound of the exhaust between the correct original cam and the later "smog" LT-1 cam. It is POSSIBLE that there is some point in the RPM range where a later GM cam might produce a slight amount of additional torque than the original 63 cam but not any that you would ever feel and certainly not worth giving up the original sound of the "Duntov" cam for.
MichaelComment
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Re: However....
Give me a break, Michael! The LT-1 cam is NOT a "smog" cam. It uses the L-72 lobe on the inlet side, indexed at 110 ATDC relative to 108 for the L-72, and the 30-30 lobe on the exhaust side, advanced four degrees to 122 BTDC indexing compared to the 30-30's 118.
Any difference in sound might be due to the earlier opening exhaust valve relative to the Duntov, but that will vary with the type of muffler. The LT-1 is likely to have a sharper exhaust note.
Both have about the same effective overlap and will pull about 12" at 900 with 25-30 degrees of total idle timing with virtually undetectable qualitative difference is idle quality.
Hundreds of engine simulations I have done show the superiority of the LT-1 cam over any other SB SHP cam, and this is backed up with actual dyno tests of real engines that I have accumulated.
DukeComment
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Re: However....
If the cams are both about the same, as you point out, then why in the world would you keep insisting everyone on the planet switch to a non stock, non original LT-1 cam??? What is your point? What's the advantage? I've made that cam switch many times in years gone by so I'll never be convinved that there is any advantage to the LT-1 cam. Also, when this current owner sells the car, how will the next owner know what cam is in it? But most of all, we're supposed to be the NCRS. The National Corvette RESTORERS Society. Random modifications and upgrades would be great on some other web site but we're supposed to be helping people put these cars back to original if that's what they want.
I can think of hundreds of modifications that would make a 63 coupe better than it was when it was new but that's not where we're supposed to be headed. The rear visibility in these cars was terrible so should recommend people saw out the split in the rear window to make it better?
If this were some safety issue or something that would be easy to return to original, I might be more willing to go along with it but installing the wrong cam has absolutely no benefit that I can see and recommending this non correct cam is absolutely pointless.Comment
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Re: However....
I have no problem with "under the cover" mods, particularly if they will improve performance and not result in loss of judging points. Bottom line is that it is up to the individual owner to make the call. I try to provide FACTS!!!
Not everyone in NCRS is concerned with being absolutely original, and I have seen plenty of non-original configurations that do not loose points, and most "restored" cars are obviously overrestored. Few looked anywhere near as perfect when they rolled off the line.
I don't think any judge that did not know that a LT-1 cam had been substituted for a Duntov could tell, and that includes experienced PV judges, so if it offers the same low end torque and idle characteristics as the Duntov, why not install it and enjoy the benefit of more top end power.
The Duntov cam was designed for the old medium port small valve heads. They had relatively "balanced" flow (75 percent exhaust/inlet flow is considered "ideal" and usually calls for inlet and exhaust lobes of equal duration), and a lobe with equal duration on both inlet and exhaust performed well. The advent of the 461 heads with better inlet flow "unbalanced" the flow and the ideal cam required more exhaust duration, but Chevrolet didn't recognize this until after the 30-30 and L-79 cams were designed. By the late sixties the relatively restrictive exhaust port was understood and the result was the LT-1 cam, and it just makes better torque bandwidth than any other SHP cam! Since it was the last SHP cam designed, one would expect that it would reflect the 15 years of small block accumulated knowledge and development.
Pocket porting 461 and similar heads results in a greater relative improvement of exhaust flow relative to inlet flow, so the heads become more "balanced" with exhaust flow being at least 75 percent of inlet flow (actually it should end up a little higher), so a cam of equal duration might be a better bet, but I've tried equal durations in many simulations with massaged heads and there is not significant improvement.
It turns out on both SBs and other engines that opening the exhaust valve early does little or no harm, but opening it too late can really hurt the top end power due to excess pumping loss.
DukeComment
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Re: However....
Duke,
You're still missing the point. It's not weather or not the LT-1 cam is better than the original 097. It's weather or not we, as an organization, should be recommending modifications at all when there's no aparent gain. If the LT-1 cam does indeed make better power at 6500 RPM, who cares!! The days of making mid 60's small block Corvettes competitive is over. Any kid with a good credit rating can buy a new Corvette and run circles around our 63's and anyone that thinks their going to impress the troops with their 360HP 63 is dreaming.
If someone wants to install a new GM 350 crate engine in their 63, that's a completely different story and I have absolutely no problem with that but trying to massage more HP out of an original engine is just so pointless, especially with a cam that has a higher torque curve, as you previously stated.
And what about the next guy that owns the car? How would he ever know what the valve lash is supposed to be if the guy he bought it from forgot to tell him the cam is a non correct LT-1. If that cam made a LOT of difference, I would be more inclined to agree with you but it doesn't so I feel the whole issue is in a negative direction.
As I mentioned previously, most owners would never feel the difference in horsepower so I feel there's nothing to be gained by installing the wrong cam. Just negatives as far as I'm concerned.
MichaelComment
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Re: And if...
This discussion must continue, it should do so between you and I. This isn't the place. You have my email address.
MichaelComment
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I have no interest *NM*
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